package com.qlogic.commons.utils.io;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.io.OptionalDataException;
import java.io.OutputStream;
import java.io.Serializable;
import java.io.ObjectStreamClass;
import java.io.ObjectInputStream;
import java.lang.reflect.Method;

import com.qlogic.commons.exceptions.BaseException;

public class SerializationUtils {

    private SerializationUtils () {
    	
    }

    // Clone
    //-----------------------------------------------------------------------
    /**
     * <p>Deep clone an <code>Object</code> using serialization.</p>
     *
     * <p>This is many times slower than writing clone methods by hand
     * on all objects in your object graph. However, for complex object
     * graphs, or for those that don't support deep cloning this can
     * be a simple alternative implementation. Of course all the objects
     * must be <code>Serializable</code>.</p>
     *
     * @param object  the <code>Serializable</code> object to clone
     * @return the cloned object
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static Object clone (Serializable object) throws BaseException {
        return deserialize( serialize(object) );
    }

    // Serialize
    //-----------------------------------------------------------------------
    /**
     * <p>Serializes an <code>Object</code> to the specified stream.</p>
     *
     * <p>The stream will be closed once the object is written.
     * This avoids the need for a finally clause, and maybe also exception
     * handling, in the application code.</p>
     *
     * <p>The stream passed in is not buffered internally within this method.
     * This is the responsibility of your application if desired.</p>
     *
     * @param obj  the object to serialize to bytes, may be null
     * @param outputStream  the stream to write to, must not be null
     * @throws IllegalArgumentException if <code>outputStream</code> is <code>null</code>
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static void serialize(Serializable obj, OutputStream outputStream) throws BaseException {
        if (outputStream == null) {
            throw new IllegalArgumentException("The OutputStream must not be null");
        }

        ObjectOutputStream out = null;
        try {
            // stream closed in the finally
            out = new ObjectOutputStream(outputStream);
            out.writeObject(obj);

        } catch (IOException ex) {
            throw new BaseException ("could not serialize", ex);
        } finally {
            try {
                if (out != null) {
                	out.close();
                }
            } catch (IOException ignored) {
            }
        }
    }

    /**
     * <p>Serializes an <code>Object</code> to a byte array for
     * storage/serialization.</p>
     *
     * @param obj  the object to serialize to bytes
     * @return a byte[] with the converted Serializable
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static byte[] serialize(Serializable obj) throws BaseException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
        serialize(obj, baos);
        return baos.toByteArray();
    }

    // Deserialize
    //-----------------------------------------------------------------------
    /**
     * <p>Deserializes an <code>Object</code> from the specified stream.</p>
     *
     * <p>The stream will be closed once the object is written. This
     * avoids the need for a finally clause, and maybe also exception
     * handling, in the application code.</p>
     *
     * <p>The stream passed in is not buffered internally within this method.
     * This is the responsibility of your application if desired.</p>
     *
     * @param inputStream  the serialized object input stream, must not be null
     * @return the deserialized object
     * @throws IllegalArgumentException if <code>inputStream</code> is <code>null</code>
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static Object deserialize(InputStream inputStream) throws BaseException {
        if (inputStream == null) {
            throw new IllegalArgumentException("The InputStream must not be null");
        }

        CustomObjectInputStream in = null;
        try {
            // stream closed in the finally
            in = new CustomObjectInputStream(inputStream);
            return in.readObject();

        } catch (ClassNotFoundException ex) {
            throw new BaseException("could not deserialize", ex);
        } catch (IOException ex) {
            throw new BaseException("could not deserialize", ex);
        } finally {
            try {
                if (in != null) {
                	in.close();
                }
            } catch (IOException ex) {
            }
        }
    }

    /**
     * <p>Deserializes a single <code>Object</code> from an array of bytes.</p>
     *
     * @param objectData  the serialized object, must not be null
     * @return the deserialized object
     * @throws IllegalArgumentException if <code>objectData</code> is <code>null</code>
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static Object deserialize(byte[] objectData) throws BaseException {
        if (objectData == null) {
            throw new IllegalArgumentException("The byte[] must not be null");
        }
        ByteArrayInputStream bais = new ByteArrayInputStream(objectData);
        return deserialize(bais);
    }


	/**
	 * Custom ObjectInputStream implementation to more appropriately handle classloading
	 * within app servers (mainly jboss - hence this class inspired by jboss's class of
	 * the same purpose).
	 */
	private static final class CustomObjectInputStream extends ObjectInputStream {

		public CustomObjectInputStream(InputStream in) throws IOException {
			super(in);
		}

		protected Class resolveClass(ObjectStreamClass osc) throws IOException, ClassNotFoundException {
			String className = osc.getName();
			Class resolvedClass = null;

			ClassLoader loader = Thread.currentThread().getContextClassLoader();
			try {
				resolvedClass = loader.loadClass(className);
			} catch(ClassNotFoundException e) {
				resolvedClass = super.resolveClass (osc);
			}

			return resolvedClass;
		}
	}
	
	public static void writeMethod (ObjectOutputStream stream, Method method) throws IOException {
		if (method != null) {
			stream.writeObject(new MethodMetaData (method));
		}
	}
	
	public static Method readMethod (ObjectInputStream stream) throws IOException, ClassNotFoundException, SecurityException, NoSuchMethodException {
		try {
			MethodMetaData methodMetaData = (MethodMetaData)stream.readObject();
			if (methodMetaData != null) {
				return methodMetaData.getClazz().getMethod (methodMetaData.getName(), methodMetaData.getArgs ());
			}
		} catch (OptionalDataException odex) {
			// ignore
		}
		return null;
	}
	
	public static void writeFile (ObjectOutputStream stream, File file) throws IOException {
		if (file != null) {
			stream.writeObject(new FileMetaData (file));
		}
	}
	
	public static File readFile (ObjectInputStream stream) throws IOException, ClassNotFoundException, SecurityException, NoSuchMethodException {
		try {
			FileMetaData fileMetaData = (FileMetaData)stream.readObject();
			if (fileMetaData != null) {
				return new File (fileMetaData.getPath ());
			}
		} catch (OptionalDataException odex) {
			// ignore
		}
		return null;
	}
	
}
